We study the effects of the oscillating axion field present in our environment on the Casimir pressure between two metallic plates. We take into account the finite conductivity of the boundary plates and model the interactions between matter and photons in the Schwinger-Keldysh formalism. This allows us to take into account dissipation in the quantum field description of this open quantum system and retrieve the Lifschitz results for the Casimir interaction between two metallic plates. We then compute the leading correction to the Lifschitz theory in inverse powers of the axion suppression scale and show that the Casimir pressure receives oscillating corrections depending on the product of the axion mass and the distance between the plates. This contribution is repulsive at large distance compared to the axion Compton wavelength as a consequence of the breaking of parity invariance by the axion dark matter background.

Leptophilic sub-MeV spin-zero dark matter (DM) decays into photons via one-loop processes, a scenario that has been in part overlooked in current literature. In this work, we provide updated and comprehensive upper limits on scalar, pseudoscalar, and axionlike DM-electron couplings based on the latest NPIPE cosmic microwave background data from Planck. Our bounds on the couplings are not only competitive with astrophysical and terrestrial experiments, but outperform them in certain regions of parameter space. Notably, we present the most stringent limits to date on scalar DM with masses around a few keV and pseudoscalar DM with masses between 100 eV and a few keV. Additionally, we explore, for the first time, the impact of implementing a cosmology-consistent treatment of energy deposition into the cosmic medium.

Recent studies using four-point correlations suggest a parity violation in the galaxy distribution, though the sensitivity of these detections is limited by the volume and accuracy of simulations used to model the noise properties of the galaxy distribution. In a recent paper, we introduced an unsupervised learning approach which offers an alternative method that significantly reduces or otherwise eliminates the dependence on mock catalogs, by learning parity violation directly from observational data. However, the convolutional neural network (CNN) model utilized by our previous unsupervised approach struggles to extend to more realistic scenarios where data is limited. We introduce a novel method, the neural field scattering transform (NFST), which enhances the wavelet scattering transform (WST) technique by adding trainable filters, parametrized as a neural field. The NFST is a general model that can flexibly and robustly capture information from a wide range of physical fields. We use the NFST for parity violation detection to demonstrate its ability to capture higher-order information. We compare the NFST’s performance at detecting parity violation in 2D mocks against WST and CNN benchmarks across varied training set sizes. We find the NFST can detect parity violation with $4\times$ less data than the CNN and $32\times$ less than the WST. Furthermore, in cases with limited data the NFST can detect parity violation with up to $6\sigma$ confidence, where the WST and CNN fail to make any detection. We identify that the added flexibility of the NFST, and particularly the ability to learn asymmetric filters, as well as the specific symmetries built into the NFST architecture, contribute to its improved performance over the benchmark models. We further demonstrate that the NFST’s detection capabilities are robust to several variations of the mock dataset, and we show that it is readily physically interpretable.

Tilts of certain elements within a laser interferometer can undesirably couple into measurements as a form of noise, known as tilt-to-length (TTL) coupling. This TTL coupling is anticipated to be one of the primary noise sources in the Laser Interferometer Space Antenna mission, after time delay interferometry is applied. Despite the careful interferometer design and calibration on the ground, TTL is likely to require in-flight mitigation through postprocessing subtraction to achieve the necessary sensitivity. Past research has demonstrated TTL subtraction in simulations through the estimation of 24 linear coupling coefficients using a noise minimization approach. This paper investigates an approach based on performing rotation maneuvers for estimating coupling coefficients with low uncertainties. In this study, we evaluate the feasibility and optimal configurations of such maneuvers to identify the most efficient solutions. We assess the efficacy of TTL calibration maneuvers by modulating either the spacecraft attitude or the moving optical subassembly yaw angle. We found that sinusoidal signals with amplitudes of around 30 nrad and frequencies near 43 mHz are practical and nearly optimal choices for such modulations. Employing different frequencies generates uncorrelated signals, allowing for multiple maneuvers to be executed simultaneously. Our simulations enable us to estimate the TTL coefficients with precision below $15\mathrm{\mu }\mathrm{m}/\mathrm{rad}$ ($1\text{−}\sigma$, in free space) after a total maneuver time of 20 min. The results are compared to the estimation uncertainties that can be achieved without using maneuvers.

We systematically perform numerical-relativity simulations for equal-mass binary neutron star mergers for the models varying the thermal index ${\mathrm{\Gamma }}_{\mathrm{th}}$ with three different equations of state (EOSs) of the neutron stars (NSs), which are consistent with current multimessenger observational data and state-of-the-art theoretical calculations, and two different binary total mass ($m_0=2.7$ and $2.9M_{\odot }$). By varying the value of ${\mathrm{\Gamma }}_{\mathrm{th}}$ within the hybrid EOS framework, we investigate the thermal effects on the merger dynamics, gravitational waves (GWs), and the dynamical mass ejection process. We find that the choice of the constant ${\mathrm{\Gamma }}_{\mathrm{th}}$ can change the outcome of the remnant for specific EOSs and $m_0$. We also show that the dynamical ejecta mass is affected by the ${\mathrm{\Gamma }}_{\mathrm{th}}$ value in a different way for different EOSs: for a stiff EOS the ejecta mass is high when ${\mathrm{\Gamma }}_{\mathrm{th}}$ is small, while for softer EOSs the largest ejecta is achieved when ${\mathrm{\Gamma }}_{\mathrm{th}}=1.3–1.4$. While the inspiral motion does not depend on the ${\mathrm{\Gamma }}_{\mathrm{th}}$ value, the postmerger phase evolution is highly affected by that. We show that the dominant peak frequency $f_2$ of the postmerger GW spectrum monotonically decreases as the ${\mathrm{\Gamma }}_{\mathrm{th}}$ increases. We find that the universal relations between NS macroscopic properties and postmerger GW frequencies are subject to non-negligible thermal uncertainties, which can obscure the universal relation between the tidal deformability and $f_2$.

Boson stars are hypothetical compact objects derived from solutions of a self-gravitating complex scalar field. In this study, we extend the traditional models by generalizing the kinetic term of the scalar field to that of a nonlinear sigma model. Concretely, we obtain spinning boson star solutions for a family of models parametrized by the curvature of their two-dimensional target manifold, as well as for various self-interaction potentials. We derive the global properties and multipolar structure of these solutions as a function of both the curvature of the target space and the strength of self-interactions. Our results suggest that a nonzero curvature in the target manifold can have a significant impact on the structure of the solutions, allowing for a range of notably different masses and degrees of compactness. However, we find that the relations between different multipoles are consistent with those for the standard complex scalar stars, and hence the universality of such relations is extended to curved target spaces.

Light primordial black holes (PBHs) may have originated in the early Universe, and could contribute to the dark matter in the Universe. Their Hawking evaporation into particles could eventually lead to the production of antinuclei, which propagate and arrive at Earth as cosmic rays with a flux peaked at GeV energies. We revisit here the antiproton and antideuteron signatures from PBH evaporation, relying on a lognormal PBH mass distribution, state-of-the-art propagation models, and an improved coalescence model for fusion into antideuterons. Our predictions are then compared with AntiMatter Spectrometer (AMS)-02 data on the antiproton flux. We find that the AMS-02 antiproton data severely constrain the Galactic PBH density, setting bounds that depend significantly on the parameters of the lognormal mass distribution, and that are comparable to or slightly stronger than bounds set from diverse messengers. We also discuss prospects for future detection of antideuterons. Given the bounds from AMS-02 antiproton data, we predict that if antideuterons were to be measured by AMS-02 or General Antiparticle Spectrometer, since the secondary contribution is subdominant, they would clearly be a signal of new physics, only part of which could, however, be explained by PBH evaporation.

Gravitationally lensed quasars have served as a powerful tool for studying the composition of dark matter (DM) in lensing galaxies. In this work, we propose a novel method to investigate stellar-mass primordial black holes (PBHs) by using the microlensing effect of strongly lensed Type Ia supernovae (SNe Ia). Using the parameters of the lensed quasar system PG $1115+80$, such as convergence, shear, and stellar/dark matter fractions, we generate microlensing magnification maps. A uniform brightness disk model is applied to these maps to evaluate the microlensing amplitude at different stages of the supernova explosion. We extend this analysis by employing the strong lensing parameters derived from the Vera C. Rubin Observatory’s Legacy Survey of Space and Time to create extensive image datasets of lensed SNe Ia. Utilizing these datasets and the Kolmogorov-Smirnov test, we compare two models: (1) the fiducial model, where galaxies are composed of stars and smooth DM, and (2) the alternative model, where galaxies consist of stars and compact DM, specifically PBHs. Our preliminary analysis predicts that at least 60 image datasets are required to distinguish these two scenarios at a 95% confidence level. Additionally, by incorporating the strong lensing halo model-based mock catalogs, which provide more realistic and precise image data, we refine our prediction to assess the data requirements for distinguishing cases where PBHs constitute fractions x of the total dark matter mass. Our findings indicate that 50, 55, and 65 image datasets, corresponding to compact dark matter fractions of 100%, 50%, and 25% (denoted by x), are necessary to distinguish between the specific models.

Sagnac speed meter and ring resonators can be used as high-precision instruments, but they are limited in their sensitivity through scattered light causing nonlinear noise. Here, we experimentally demonstrate a technique called tunable coherence, where the long coherence length of the laser is broken in a controlled way, to suppress the coupling of scattered light in a Sagnac interferometer. We demonstrate a scattered light suppression of 24.2 dB in a Sagnac interferometer and discuss the experimental limitations. Further, we show an analytical discussion on how tunable coherence could be a fundamental solution to light scattering back from optical surfaces into the counterpropagating beam, which is an issue particularly in ring resonators.

We study the scattering of the gluon-dressed physical quarks, defined as the eigenstates of the vacuum QCD Hamiltonian, off a colored medium. We solve the wave function of the physical quark state by diagonalizing the QCD Hamiltonian in vacuum in a $|q⟩+|qg⟩$ Fock space, with implementing the sector-dependent mass renormalization scheme. We then perform numerical simulations of the real-time quantum state evolution of the initially dressed quark state at various medium densities. The results are compared with those of an initially bare or off-shell quark states. With the obtained light-front wave function of the evolved state, we extract the quark jet transverse momentum broadening, the quenching parameter, the cross section, the gluon emission rate, and the evolution of the invariant mass. The scenario considered is relevant for high energy scattering processes, where the quark originates from far outside the color field describing the scattering target. This investigation on dressed quarks complements our earlier studies of the single quark scattering in the $|q⟩$ Fock space, and of the bare quark scattering in the $|q⟩+|qg⟩$ Fock space, providing a novel systematic description of quark scattering process using a nonperturbative formalism.

We consider an extension of the Standard Model with one or more scalar multiplets beyond the Higgs doublet $\mathrm{\Phi }$. The additional scalar multiplets are supposed to carry arbitrary hypercharges (the precise conditions on the scalar potential are less stringent). We prove that, in such a model, if the field configuration where only $\mathrm{\Phi }$ has a nonzero vacuum expectation value (VEV) is a local minimum of the potential, then it has a lower value of the potential than any extremum where both $\mathrm{\Phi }$ and other scalar multiplets have nonzero VEVs.

We present a model-independent method to study the four-body decay $B\to K^{*}(\to K^{+}{\pi }^{-}){\mu }^{+}{\mu }^{-}$, based on extracting continuous observables with a moments approach. The method allows the observables to be determined unbinned in both the dilepton and $K^{+}{\pi }^{-}$ invariant masses on which the decay dynamics depend. This will allow the method to shed new light on how the observables depend on the $P$- and $S$-wave contributions to the $K^{+}{\pi }^{-}$ system. This approach contrasts with the state-of-the-art analyses, which bin in dilepton and $K^{+}{\pi }^{-}$ mass or use a model for the dependence of the underlying decay amplitudes on these masses. The method does not require making a statistical fit and so avoids problems of biases and poor uncertainty estimation when dealing with small samples or a large number of fit parameters. We provide the Standard Model predictions for the unbinned optimized observables, derive new geometrical bounds on their values, and study the robustness of these bounds in the presence of a scalar new physics contribution. We explore the zero-crossing points of $P_2$ and $P_{4,5}^{\prime }$ observables as a function of a new physics contribution to the dominant vector Wilson coefficient, $C_9^{\mathrm{NP}}$. We also discuss the conditions that can be used to test the theoretical model of the amplitudes needed for an experimental amplitude analysis. Finally, as an illustration, we show how the proposed method might be used to extract the zero-crossing points, make a comparison with the bounds and test a nontrivial relation between the observable values.

Parametric resonance can produce particles from an oscillating scalar field, where an exponential growth of the particle number density can be developed. While it has been noticed that stimulated decay in Boltzmann equations exhibits similar parametric dependence of the exponential growth, it is not yet quantitatively clear under what circumstances the two phenomena can reconcile. We demonstrate that trilinear particle interaction in the Boltzmann equation can provide a good approximation to describe the distribution function and the number density in the asymptotic regime of narrow parametric resonance. We find that the crucial treatment leading to the quantitative agreement is a proper Gaussian simulation of the momentum spread inherited from nonrelativistic particle decay. With the simple particle picture, the analytic Boltzmann approximation can be applied to explosive photon production from axions/axionlike particles and to dark matter production from oscillating fields.

The observation of the medium response generated by the propagation of high energy partons in the quark gluon plasma produced in heavy-ion collisions would provide clear and unmistakable evidence for the hydrodynamic behavior of the bulk. Recently, it has been argued that the features of the medium’s backreaction to the jet could be cleanly imprinted in the correlations of asymptotic energy flows, in principle, allowing one to isolate this signal from other uncorrelated physical processes. Nonetheless, the current limited theoretical understanding of these jet observables in heavy-ion collisions constrains their applicability as probes of the medium (hydro)dynamics. In this work, we provide an analytic picture for the medium backreaction’s effect on the energy flux and two point energy correlator. We show that the medium response leads to the emergence of a universal classical scaling law, competing with the perturbative QCD contribution at large angles. Comparing the associated correlator to recent experimental measurements, we find that the observed large angle features can be qualitatively described by a purely hydrodynamically driven response and its interplay with the hard jet component.

Machine learning is becoming increasingly popular in the context of particle physics. Supervised learning, which uses labeled Monte Carlo (MC) simulations, remains one of the most widely used methods for discriminating signals beyond the Standard Model. However, this paper suggests that supervised models may depend excessively on artifacts and approximations from Monte Carlo simulations, potentially limiting their ability to generalize well to real data. This study aims to enhance the generalization properties of supervised models by reducing the sharpness of local minima. It reviews the application of four distinct white-box adversarial attacks in the context of classifying Higgs boson decay signals. The attacks are divided into weight-space attacks and feature-space attacks. To study and quantify the sharpness of different local minima, this paper presents two analysis methods: gradient ascent and reduced Hessian eigenvalue analysis. The results show that white-box adversarial attacks significantly improve generalization performance, albeit with increased computational complexity.

We study the glueball properties at finite temperature from the temporal correlation in $SU(3)$ Yang-Mills theory using anisotropic lattice QCD. Although the existence of a constant contribution to the meson correlation function appearing in the deconfinement phase is known, its effect on the glueball correlation function at finite temperature has not been considered in previous studies. The present study reveals that the constant contribution to the glueball correlation function actually occurs in the three lowest-lying glueball states, corresponding to the $0^{++}$, $2^{++}$, and $0^{-+}$ glueballs, from near the critical temperature of the deconfinement phase transition $T_C$ to the high-temperature side. If the existence of constant terms is taken into account in the standard pole-mass analysis, it is observed that the pole mass of the glueball ground state remains unchanged below $T_C$ and then increases with temperature above $T_C$. The result indicates that the true temperature dependence of the glueball mass above $T_C$ is opposite to the results of the previous studies.

We study systems of two and three mesons composed of pions and kaons at maximal isospin using four CLS ensembles with $a\approx 0.063\mathrm{fm}$, including one with approximately physical quark masses. Using the stochastic Laplacian-Heaviside method, we determine the energy spectrum of these systems including many levels in different momentum frames and irreducible representations. Using the relativistic two- and three-body finite-volume formalism, we constrain the two- and three-meson K matrices, including not only the leading $s$ wave, but also $p$ and $d$ waves. By solving the three-body integral equations, we determine, for the first time, the physical-point scattering amplitudes for $3{\pi }^{+}$, $3K^{+}$, ${\pi }^{+}{\pi }^{+}{K}^{+}$, and $K^{+}{K}^{+}{\pi }^{+}$ systems. These are determined for total angular momentum $J^P=0^{-}$, $1^{+}$, and $2^{-}$. We also obtain accurate results for $2{\pi }^{+}$, ${\pi }^{+}{K}^{+}$, and $2K^{+}$ phase shifts. We compare our results to chiral perturbation theory and to phenomenological fits.

We investigate properties of the topological charge for several $SU(N_C)$ gauge field ensembles for $N_C=4$, 5, 6 with a single fermion in the two-index antisymmetric representation, covering multiple lattice spacings at otherwise approximately constant physical parameters. Comparing the topological charge defined by the Wilson flow and the overimproved DBW2 flow we find that already at small flow times the latter stabilizes on discrete values. We provide evidence that as the lattice spacing is lowered the Wilson flow also separates into discrete sectors at earlier flow times. Adopting the DBW2 definition in the remainder of the analysis, we do not see any evidence of fractional topological charges, which could in principle appear at finite lattice spacing.

The refined Gribov-Zwanziger scenario is a local and renormalizable setup in which infinitesimal Gribov copies are eliminated and further nonperturbative effects are accounted for. The gluon propagator that arises from this framework fits lattice data very well in the Landau gauge. We investigate the coupling of quarks to this setting at one loop order by computing the quark propagator. The fermionic sector is introduced by a minimal coupling and the nonperturbative effects are transmitted to the matter sector through gluonic loops which, in this case, carry information from the elimination of infinitesimal Gribov copies and the formation of condensates. We compare our findings with available lattice data both for the unquenched gluon propagator as well as for the quark propagator in the Landau gauge. Our results are comparable with those obtained in the Curci-Ferrari model at one loop order. In particular, we are able to fit the unquenched gluon propagator and use the fixed parameters to predict the quark mass function and find good agreement with lattice data. However, the quark dressing function does not agree, even at a qualitative level, with lattice data in the infrared. This is agreement with the analog computation in the Curci-Ferrari model. Inspired by the developments in the Curci-Ferrari results, such a disagreement is likely to be cured by the inclusion of two-loop corrections. Finally, we compare the present minimal coupling with a nonperturbative matter coupling proposed in the refined Gribov-Zwanziger literature.

Future planned lepton colliders, both in the circular and linear configurations, can effectively work as virtual and quasireal photon-photon colliders and are expected to stimulate an intense physics program in the next few years. In this paper, we suggest to consider photon-photon scattering as a useful source of information on transverse-momentum-dependent fragmentation functions (TMD FFs), complementing semi-inclusive deeply inelastic scattering and $e^{+}{e}^{-}$ annihilation processes, which provide most of the present phenomenological information on TMD FFs. As a first illustrative example, we study two-hadron azimuthal asymmetries around the jet thrust axis in the process ${\ell }^{+}{\ell }^{-}\to {\gamma }^{*}\gamma \to q\overline{q}\to h_1{h}_2+X$, in which in a circular lepton collider one tagged, deeply virtual photon scatters off an untagged quasireal photon, both originating from the initial lepton beams, producing inclusively an almost back-to-back light-hadron pair with large transverse momentum, in the ${\gamma }^{*}\gamma$ center-of-mass frame. Similar processes, in a more complicated environment due to the presence of initial hadronic states, can also be studied in ultraperipheral collisions at the LHC and the planned future hadron colliders.